MZ expansion in KSHV latency locus transgenic mice. (A) Splenocytes from wild-type (WT) or latency transgenic mouse (TG) were analyzed by fluorescence-activated cell sorter (FACS). CD19⁺CD24⁺ cells were further gated with CD21 and CD23. Percentages of CD19⁺CD24⁺CD21hiCD23^- cells among whole lymphocytes are indicated in FACS profiles. (B) Alternatively, CD19⁺IgD^- cells were gated with CD21 and CD23 in an independent analysis. (C) Bar plot of flow cytometry data from panels A-B (n = 5 for WT and n = 9 for the transgenic mice). (D) MZ precursor cells were gated as CD19⁺IgD⁺CD21hiCD23⁺. Average percentages of 6 WT and 9 latency transgenic (TG) mice are shown with the standard deviation. (E) Frozen spleen sections were stained with B220 (green) for B cells and MOMA-1 for marginal zone macrophages (red). Magnification ×200. FL, follicle.